DLC薄膜对TC4钛合金微动磨损行为的影响

Effect of DLC Film on Fretting Wear Behavior of TC4 Titanium Alloy

目的为提高TC4钛合金的抗微动磨损性能,对比研究类金刚石薄膜(DLC)和TC4钛合金在干摩擦条件下的微动磨损行为,揭示DLC薄膜抗微动磨损的机理。方法在TC4钛合金基体上利用非平衡磁控溅射技术制备DLC薄膜。利用原子力显微镜、拉曼光谱和纳米压痕仪分析薄膜的表面形貌、物相组成以及纳米硬度。利用球/平面接触形式SRV-V微动摩擦磨损试验机研究DLC薄膜和TC4钛合金的微动摩擦磨损性能。采用激光共聚焦显微镜和自带能谱分析仪的场发射扫描电镜分析材料的磨痕情况。通过Ft-D-N曲线、三维轮廓、磨损形貌及磨痕化学成分分析来揭示DLC薄膜和TC4钛合金微动损伤机理。结果DLC薄膜与TC4钛合金相比,摩擦因数和磨损体积都很小。载荷为10 N时,DLC薄膜的摩擦因数为0.01~0.03,TC4钛合金的摩擦因数为0.07~0.12。从磨损率来看,TC4钛合金的磨损率随着位移幅值的增大而增大,DLC薄膜的磨损率随着位移幅值的增大而减小。位移幅值为100μm时,TC4钛合金的磨损率取得最大值(5.02×10−5 mm3/(N·m)),DLC薄膜的磨损率取得最小值(6.70×10−8 mm3/(N·m))。TC4钛合金磨损严重,磨损机制为粘着磨损、磨粒磨损、疲劳剥层和氧化磨损,同时伴随有塑性变形;而DLC薄膜磨损轻微,磨损机制以磨粒磨损为主。结论DLC薄膜具有较高的硬度和良好的润滑特性。在干摩擦条件下,DLC薄膜可以显著提高TC4钛合金的抗微动磨损性能。

To improve the fretting wear resistance of TC4 titanium alloy,DLC films were deposited on TC4 titanium alloy by unbalanced magnetron sputtering technology.The fretting wear behavior of DLC film and TC4 titanium alloy were comparatively investigated in a condition of dry friction,which reveals the mechanism of DLC film on the fretting wear resistance.The surface morphology,phase composition and nano-hardness of the films were analyzed by atomic force microscope,Raman spectroscopy and Nanoindentation tester.The fretting friction and wear performance of DLC film or TC4 alloy was studied by SRV-V fretting friction tester with a ball/plane contact configuration.The wear tracks of the materials were characterized by laser confocal microscope and field emission scanning electron microscope with DES analysis.The fretting damage mechanism was revealed by the analysis of Ft-D-N curve,three-dimensional profile,wear morphology and wear chemical composition.Compared with TC4 alloy,the DLC film exhibited very low friction coefficient and wear volume.At a normal load of 10 N,friction coefficient of the DLC film ranged between 0.01~0.03 while that of TC4 substrate ranged between 0.07~0.12.The wear rate of TC4 titanium alloy increased with increased displacement amplitude.In contrast,the wear rate of DLC film decreased with increased displacement amplitude.Under the displacement amplitude of 100μm,the wear rate of the TC4 alloy was largest as 5.02×10−5 mm3/(N·m),while that of the DLC film was the lowest as 6.70×10−8 mm3/(N·m).The wear of TC4 alloy was serious and the wear mechanism is adhesive wear,abrasive wear,fatigue peeling and oxidative wear,accompanied by plastic deformation,while the wear of DLC film was slight and the wear mechanism is dominated by abrasive wear.It can be concluded that DLC film has higher hardness and good lubricating properties.Under dry friction conditions,the DLC film can effectively improve the fretting wear resistance of TC4 alloy.